Power feeding method, continuous electrolytic plating apparatus for web and method for manufacturing plastic film with plated coating film

ABSTRACT

Two rotating members placed to face each other and nipping a web such that only an end of the web provided with conductivity is pressed are provided, at least one of the rotating members serves as a feeding electrode, and these rotating members are rotated about the same velocity to a transportation velocity of the web.

This is a U.S. National Phase application of application numberPCT/JP2007/056145, filed Mar. 26, 2007 (which is incorporated herein byreference in its entirety), which claims priority benefit of JP2006-091496 filed Mar. 29, 2006.

FIELD OF THE INVENTION

The present invention relates to a power feeding method, a continuouselectrolytic plating apparatus for web, and a method for manufacturing aplastic film with a plated coating film.

BACKGROUND OF THE INVENTION

As a conventionally known method for continuously forming a platedcoating film, such as a plastic film, on a web while transporting theweb, a conductive surface of the web or a metallic web contact is madeto contact a cathode roller, and a plating bath in which an anode isplaced is provided before or after the cathode roller, so that theplated coating film is formed by the plating bath. In the case where theplated coating film is continuously formed on the web according to themethod, wherein the web continuously travels through the unit providedwith the cathode and anode, a plated coating film having a desirablylarge thickness can be easily formed on the web (see the Patent Document1).

As an example of a substrate used for flexible circuit which has beenincreasingly often used in an electronic device, an electroniccomponent, a semiconductor package and the like in recent years, awiring substrate, wherein a polyimide film or a polyester film and acopper foil are bonded to each other, is attracting attention. There aretwo different types of the substrate used for flexible circuit thusconstituted, which are so-called “triple-layered type”, where a copperfoil is bonded to the web via an adhesive, and so-called “double-layeredtype”, where a metallic coating film is formed on the web by means ofthe plating without any adhesive. Of these two different substrates, thelatter “double-layered type” substrate is more spotlighted these days intandem with the advancements in the miniaturization of circuit wiringpitches.

The current status relating to the substrate for flexible circuit isdescribed below. The triple-layered substrate for print circuit, whereinepoxy-based resin or acrylic resin is used as the adhesive, isdisadvantageous in that its electric characteristics are deteriorateddue to impurity ions included in the material of the adhesive. Further,in the case where polyimide is used as a base film material, it is notpossible to fully take advantage of such a high heat resistance thereof(at least 300° C.) because a heat-resistant temperature of the adhesiveis at most 100-150° C. Therefore, it is inevitable to reduce thespecification of a heating temperature in the wire bonding for an ICchip for which high temperatures are demanded in the mounting process.In the triple-layered substrate for print circuit, the copper usedtherein is too thick for such a patterning as at most 80 μm pitch(copper wiring 40 μm, gap 40 μm) because the copper foil is generally asthick as 18 μm or 35 μm, and an etching ratio is thereby significantlyreduced. As a result, a large difference is generated between asurface-side circuit width and an adhesive-side circuit width of thecopper foil or a whole circuit width is significantly reduced due to theetching, which disadvantageously results in the failure to obtain atargeted circuit pattern.

Therefore, the so-called “double-layered type” substrate was proposed inorder to solve the problems in the triple-layered type substrate thusdescribed. The so-called “double-layered type” substrate is obtainedsuch that the electrolytic copper plating is applied after variousmetals are deposited on the web surface by means of the variousdeposition processes such as the PVD process such as vacuum deposition,sputtering process or various ion plating processes and so-called CVDprocess wherein chemicals including metals are vaporized and therebydeposited, or various metals are plated by means of the electrolessplating in place of the adhesive. The “double-layered type” substrate ischaracterized in that a copper film thickness can be arbitrarily changedby the electrolytic copper plating, wherein a 40 μm-pitch circuitpattern can be generated in a simple manner provided that the thicknessof the copper film is 8 μm, and heat resistant temperatures of differentwebs can be directly reflected thereon.

In order to respond to the current status thus far described, there is ahigh demand for a film having a plated coating film. However, in theconventional method, wherein the conductive surface of the web incontact with the cathode roller is transported as described earlier,scratches and burred protrusions resulting from the scratches may begenerated on the conductive surface of the web which is rathervulnerable. Further, an entire length of the cathode roller, whichcontacts an entire width of the web, is increased as the width of theweb is increased, which makes it necessary to increase a diameter of theroller in order to maintain the strength. As a result, the power feedingapparatus is unfavorably increased in size.

The miniaturization of the circuit pattern has been advancing in recentyears, and an increasing higher surface quality has been accordinglydemanded for the plated coating film. Therefore, the development of aprocess capable of preventing the generation of very small scratches andprotrusions is aggressively moving forward.

The Patent Document 2 proposed a process called a clipping method,wherein an end of the web is nipped with feeding clips, and theend-nipped web is carried through the plating liquid to be plated.According to the method, wherein only the end of the web, which will beremoved when the web is finalized as a product, is nipped, no minorscratches or the like are generated in the product, and the surfacethereby obtained has a good quality. However, a heavily-developedadditional facility, which includes a large-sale transportation systemfor transporting the feeding clips, a process for removing the platedcoating film deposited on the feeding clips and the like, becomesnecessary. Further, it is demanded that the plating liquid be as leastpolluted as possible because foreign matters floating in the platingliquid may disadvantageously roughen the plated surface. However, theplating liquid, in fact, is easily polluted by such foreign matters asabrasion powder because various moving units are placed above theplating liquid. Further, the section nipped with the feeding clips isnot plated, and a resistance value is increased because the filmthickness of the conductive film is reduced only in the section. As aresult, a periphery of the section may be color-changed or altered bythe Joule heat generated when large currents are supplied.

The Patent Document 3 recites a plating method wherein a feedingelectrode having a plate spring shape is pushed against the end of theweb to supply power to the web so that the web is plated. The method canalso provide such a good surface quality that scratches or the like arenot included in the final product. However, the feeding electrode iseasily worn because it is constantly in close contact with the web, andthe plating liquid and peripheral devices are polluted by powdergenerated by the abrasion. Further, the presence of the electrodeconstantly applies the brake to the web, and a tensile forcedistribution is thereby generated in the width direction of the web,which may significantly disturb the transportation of the web in astable manner.

The Patent Document 4 recites an example of a conventional vertical-typeplating device in which a feeding electrode having a roller shape isprovided. In the example, a feeding electrode having a so-calleddumbbell shape in which an outer diameter of the roller at the center isreduced so that both ends thereof alone contact the web was proposed asone of possible shapes of the cathode roller. According to the method, aproduct, in which the surface flaw such as scratches is reduced at thecenter of the web not contacted by the roller, can be produced. However,an angular velocity of the roller is equal at the both ends, andtherefore, a circumferential velocity is different at the both ends evenif a very small difference is generated between outer diameters of theboth ends contacting the web. Therefore, a remarkably high workingprecision is demanded. When the high precision cannot be obtained by anypossibility, such a problem that the electrode may be worn or thetensile force distribution may be generated in the width directionbecause one of the ends slidably contacts the web.

The Patent Document 5 recites a feeding method wherein while any contactof the center of the web is avoided in order to realize the platingwithout undermining the characteristics of unwoven fabric such as itsbulkiness, and only an upper end of the web is exposed out of theplating bath, so that a belt-like electrode is brought into closecontact with the exposed part so as to supply power. The method can alsoprovide the plated film having such a high quality that no scratches orbruises are generated at the center, however, the film in the upper endof the web, which is not constantly plated, is very thin and subject toa large resistance. Therefore, the film is color-changed and altered bythe Joule heat generated when large currents are supplied. Further, inthe case of a web such as a plastic film which is poor in its elasticityin a thickness direction, when the web and the belt-shape electrode arenipped with guide rolls so that they are brought into close contact witheach other by a nipping force, a contact resistance between theelectrode and the web other than the nipped section is unfavorablyincreased because they tightly contact with each other only at theguide-roll section. Therefore, heat-related problems may be generatedwhen large currents are supplied.

The Patent Document 6 recites a transporting method, wherein a rotatingmember having a small width is pressed onto a transportation roller. Therotating member can also serve as the feeding electrode. When therotating member is set at the end of the web as the feeding electrodeaccording to the method, a product in which flaws are reduced on asurface opposite to a surface tightly contacting the transportationroller can be manufactured. According to the inventors of the presentinvention, however, the method requires a roller made of a hard materialbecause creases are unfavorably generated on the web by the edge of theelectrode in the case where a soft material is used for thetransportation roller. As a result, the flaws possibly generated on thesurface tightly contacting the transportation roller may not beprevented.

-   Patent Document 1: No. H07-22473 of the Japanese Patent Application    Laid-Open-   Patent Document 2: No. 2005-507463 of the Japanese Translation of    the PCT Applications-   Patent Document 3: No. 2005-248269 of the Japanese Patent    Application Laid-Open-   Patent Document 4: No. 2003-321796 of the Japanese Patent    Application Laid-Open-   Patent Document 5: No. H08-209383 of the Japanese Patent Application    Laid-Open-   Patent Document 6: No. 2004-263215 of the Japanese Patent    Application Laid-Open

SUMMARY OF THE INVENTION

The present invention provides an electrolytic plating apparatus capableof preventing the generation of fine flaws on a plated coating film.

The present invention relates to a power feeding method for anelectrolytic plating method for electrolytically plating a webcomprising a conductive surface as at least one of surfaces thereof in aplating tub while continuously transporting the web, wherein the web isnipped with at least two rotating members so that the web faces one endthereof or both ends thereof in a width direction, at least one of therotating members is used as a feeding electrode so that the web ispower-supplied, the electrode is pressed onto the web only in a regiondistant by at least 0.5 mm and at most 20 mm from the end of the web inthe width direction with a contacting pressure of at least 0.5 N and atmost 100 N per 1 mm of a contact width in the width direction, and therotating members are rotated about the same velocity to a velocity ofthe transportation of the web.

An exemplary embodiment of the present invention relates to a powerfeeding method for an electrolytic plating method for electrolyticallyplating a web having conductivity on surfaces thereof in a plating tubwhile continuously transporting the web, wherein the web is nipped withat least two rotating members so that the web faces one end thereof orboth ends thereof in a width direction, at least one of the rotatingmembers is used as a feeding electrode so that the web ispower-supplied, the electrode is pressed onto the web only in a regiondistant by at least 0.5 mm and at most 20 mm from the end of the web inthe width direction with a contacting pressure of at least 2 N and atmost 100 N per 1 mm of a contact width in the width direction, and therotating members are rotated about the same velocity to a velocity ofthe transportation of the web.

In the power feeding method according to another exemplary embodiment ofthe present invention, only the electrode placed outside of the platingtub is used, and power is supplied in a section of the web targeted forthe plating only in an upstream side and/or a downstream side of theplating tub in the transportation direction.

In the power feeding method according to still another exemplaryembodiment of the present invention, the web is transported in alongitudinal direction so that the width direction thereof is along avertical direction.

In the power feeding method according to still another exemplaryembodiment of the present invention, the rotating member on a receivingside which nips the web together with the feeding electrode comprises anelastic member on a surface layer thereof.

In the power feeding method according to still another exemplary,embodiment of the present invention, the feeding electrode comprises anelectrically conductive layer on a surface layer thereof and an elasticlayer inside the electrically conductive layer.

In the power feeding method according to still another exemplaryembodiment of the present invention, a contact width between thereceiving-side rotating member and the web in the width direction islarger by at least 1 mm and at most 15 mm than a contact width betweenthe feeding electrode and the web in the width direction.

In the power feeding method according to still another exemplaryembodiment of the present invention, the contact width between thereceiving-side rotating member and the web in the width direction issmaller than the contact width between the feeding electrode and the webin the width direction.

In the power feeding method according to still another exemplaryembodiment of the present invention, a contact pressure is applied sothat a contact area where the feeding electrode contacts the conductivesurface satisfies the following numeral formula.

$\begin{matrix}{\frac{I^{2} \cdot R}{Q \cdot t} \leqq A \leqq 1000} & {{NUMERAL}\mspace{14mu}{FORMULA}\mspace{14mu} 1}\end{matrix}$A: contact area between the feeding electrode and the conductive surface[mm²]I: current value supplied to the feeding electrode [A]R: contact resistance value in the contact between the feeding electrodeand the conductive surface [Ω]t: thickness of the electrically conductive layer on the conductivesurface where the feeding electrode contacts the conductive surface [mm]

Q: threshold heat quantity factor [W/mm³]=5.5×10³

Still another exemplary embodiment of the present invention relates to acontinuous electrolytic plating apparatus for web for electrolyticallyplating a web comprising a conductive surface as at least one ofsurfaces thereof in a plating tub while continuously transporting theweb, comprising at least two rotating members placed to face each otherand nipping the web to be pressed onto one end of the conductive surfacein a width direction, wherein at least one of the rotating membersconstitutes a feeding electrode, and the rotating members are rotatedabout the same velocity to a velocity of the transportation of the web.

In the continuous electrolytic plating apparatus for web according tostill another exemplary embodiment of the present invention, wherein theelectrode is provided solely outside the plating tub.

The continuous electrolytic plating apparatus for web according to stillanother exemplary embodiment of the present invention comprises atransporting device which transports the web in a longitudinal directionso that the width direction of the web is along a vertical direction,wherein the feeding electrode is provided to be pressed onto only anupper end of the web.

Still another exemplary embodiment of the present invention relates to acontinuous electrolytic plating apparatus for web for electrolyticallyplating a web comprising a conductive surface as at least one ofsurfaces thereof in a plating tub while continuously transporting theweb, comprising at least two rotating members placed to face each otherand nipping the web to be pressed onto both ends of the conductivesurface in a width direction, wherein at least one of the rotatingmembers constitutes a feeding electrode, and the rotating members arerotated about the same velocity to a velocity of the transportation ofthe web.

In the continuous electrolytic plating apparatus for web according tostill another exemplary embodiment of the present invention, therotating member on a receiving side which nips the web together with thefeeding electrode has an elastic member on an outermost layer thereof.

In the continuous electrolytic plating apparatus for web according tostill another exemplary embodiment of the present invention, the feedingelectrode comprises an electrically conductive layer on a surface layerthereof and an elastic layer inside the electrically conductive layer.

In the continuous electrolytic plating apparatus for web according tostill another exemplary embodiment of the present invention, a contactwidth between the receiving-side rotating member and the web in thewidth direction is larger by at least 1 mm and at most 15 mm than acontact width between the feeding electrode and the web in the widthdirection.

In the continuous electrolytic plating apparatus for web according tostill another exemplary embodiment of the present invention, the contactwidth between the receiving-side rotating member and the web in thewidth direction is smaller than the contact width between the feedingelectrode and the web in the width direction.

Still another exemplary embodiment of the present invention relates to amulti-stage continuous electrolytic plating apparatus for web, wherein aplurality of the plating tubs are provided, the feeding electrode isplaced outside the plating tub in an upstream side and/or a downstreamside in a transportation direction of the respective plating tubs, theweb is continuously thrown into the respective plating tubs so that adesirable plating film thickness is obtained, and the respective platingtubs are adapted such that the following numeral formula is satisfied.

$\begin{matrix}{\frac{B}{2} < X \leqq \frac{500 \cdot N \cdot W}{\left( {I \cdot W \cdot L} \right)^{2} \cdot p \cdot {\log\left( \frac{t + W}{t} \right)}}} & {{NUMERAL}\mspace{14mu}{FORMULA}\mspace{14mu} 2}\end{matrix}$X: distance in the transportation direction of the web between thefeeding electrode and a gateway of the plating tub which is the closestto the center of rotation of the rotating member in contact with the web[mm]B: length of a power feeder in the transportation direction [mm]I: current density [A/dm²]W: width of the conductive surface [mm]L: length of the plating tub in the transportation direction [mm]ρ: conductive film surface resistivity of the film with the conductivefilm to be thrown into the plating tub [Ω/□]t: contact width between the feeding electrode and the conductivesurface in the width direction [mm]N: feeding electrode factor (2 in the case where it is provided on bothsides, 1 in the case where it is provided on one side)

Still another exemplary embodiment of the present invention relates to amethod for manufacturing a plastic film with a plated film, wherein aplastic film is used as the web, and the power feeding method or thecontinuous electrolytic plating apparatus is used in at least a part ofmanufacturing steps.

In an embodiment of the present invention, “the conductivity ispossessed” when the surface resistivity is at most 100Ω/□.

The “conductive surface” denotes one of the surfaces of the web havingconductivity. Only one of the surfaces may be the conductive surface,and the both surfaces may be the conductive surfaces.

A mechanism which applies at least a force allowing the web to traveland a mechanism which guides the web constitute the “transportingdevice”. Examples of the transporting device include a group oftransportation rollers and a belt conveyer.

“The rotating member is rotated about the same velocity to atransportation velocity of the web” means that the rotating member isrotated such that a difference between the circumferential velocity ofthe rotating member and the transportation velocity of the web is atmost ±10%. The velocity difference is preferably smaller, and therotating member is preferably rotated with a velocity difference at most±5%, and more preferably rotated with a velocity difference at most ±1%.The rotating member may be rotated about the same velocity in such amanner that is driven by the web, or the rotating member may beaggressively driven and thereby synchronized with the transportationvelocity of the web.

“The section of the web targeted for the plating” denotes a sectionsubjected to the plating in the plating tub.

The “surface resistivity” denotes a resistance value per unit area. As amethod for measuring it, the four-probe method is adopted pursuant tothe JIS K7194-1994, and the surface resistivity can be obtained when apart relating to a thickness is ignored. The unit is “Ω”, however, “Ω/□(ohm per square), which is conventionally used as the unit of thesurface resistivity, is adopted in order to clearly distinguish it fromthe resistance value “Ω”.

In an embodiment of the present invention, the contact width between thereceiving-side rotating member and the web in the width direction ispreferably larger than the contact width between the feeding electrodeand the web in the width direction by at least 1 mm and at most 15 mmbecause the contact resistance between the feeding electrode and thefilm conductive surface can be reduced. In the case where the surfacelayer of the receiving-side rotating member is elastic, the feedingelectrode may have such a shape that is deformed into the receiving-siderotating member, which possibly generates creases in the web. However,this section, which will be finally cut off, is not included in a finalproduct.

In an embodiment of the present invention, the contact width between thereceiving-side rotating member and the web in the width direction ispreferably smaller than the contact width between the feeding electrodeand the web in the width direction because the deformation of thereceiving-side rotating member which may be increased by an intensivepressure applied thereto is not extended to be larger than the contactwidth of the feeding electrode in the contact width direction, whichprevents the generation of creases or the like in the web. The contactwidth between the receiving-side rotating member and the web in thewidth direction is preferably smaller than the contact width between thefeeding electrode and the web in the width direction by at least 0.5 mmand at most 5 mm.

According to one aspect of the present invention, the conductive surfaceof the web can be plated without any contact of the metallic memberconstituting the feeding electrode with the surface of the web whichwill be included in the final product, the generation of scratches andfine protrusions resulting from the scratches can be controlled, and theplated film with a high quality in which the surface flaws are reducedcan be provided. In addition, when the web is nipped with a linearpressure at least 0.5N/mm, the contact resistance between the feedingelectrode and the web conductive surface can be reduced, which preventsthe film from color-changing and altering owing to the heat generationin vicinity of the feeding electrode. Further, any possible force whichmay act against the transportation of the web can be controlled becausethe feeding electrode is the rotating member, which allows the web to bestably transported. Further, the materials causing the pollution such asthe abrasion powder are not generated.

Further, the dimension of the feeding electrode can be reduced, whichleads to the reduction of the dimension of the power feeding apparatusitself. As a result, the length of the plating tub can be extendedwithout any increase in the dimension of the apparatus, whichcontributes to the improvement of productivity and the reduction ofcosts for the apparatus.

According to exemplary embodiments of the present invention, wherein thefeeding electrode is provided solely outside the plating tub, thefeeding performance can be stabilized because the deposition of theplating metal on the feeding electrode itself can be prevented, and anadditional step such as a plating removal step becomes unnecessary. As aresult, the costs for the apparatus can be reduced. Further, the heatgeneration resulting from the film resistance of the contact area of thefeeding electrode can be controlled because the contact area of thefeeding electrode is also plated.

Further, a larger voltage was conventionally necessary in the case wherethe film resistance of the web conductive film was large even though theplating was performed with the same current density. However, in thepresent exemplary embodiment, the plating can be realized with a smallvoltage because the distance from the rotational center of the feedingelectrode to the inlet of the plating tub is optimized. As a result,power consumption can be reduced.

The present invention according to one aspect, wherein the plastic filmas a flexible web can be stably transported, is suitable for themanufacturing of a plastic film with a plated film, and more suitablyapplied when copper, which is relatively soft and easily damaged, isplated. The effects of the invention, which are to control the surfaceflaws and to stably transport the web, can be most effectively exertedin the manufacturing of a substrate for flexible circuit for which ahigh surface quality is demanded.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic plan view of an example of a continuouselectrolytic plating apparatus for web according to a preferredembodiment of the present invention.

FIG. 1B is a schematic perspective view in which vicinity of anelectrode as an example of a power feeder is enlarged.

FIG. 1C is a schematic sectional view illustrating a structure of anexample of the feeding electrode.

FIG. 1D is a schematic sectional view illustrating a structure of anexample of the feeding electrode.

FIG. 2 is a graph illustrating an example of a relationship between apressure and a contact resistance.

FIG. 3 is a conceptual view illustrating a method for measuring acontact resistance between the feeding electrode and a film conductivesurface.

FIG. 4 is a graph illustrating a relationship between the pressure andthe contact resistance.

FIG. 5 is a conceptual view illustrating a method for measuring aresistance value with a different conducting length.

FIG. 6 is a graph illustrating a relationship between the conductinglength and the resistance value.

FIG. 7 is a conceptual view illustrating a method for measuring acontact resistance between an electrode having a roller shape used in acomparative example and the film conductive surface.

FIG. 8 is a conceptual view illustrating a method for measuring acontact resistance in the roller-shape electrode used in the comparativeexample when the conducting length is changed.

FIG. 9 is a graph illustrating a relationship between the pressure andthe contact resistance.

EXPLANATION OF SYMBOLS

-   11 film with conductive film-   111 plastic film-   112 conductive film-   12 wind-off section-   13 preparatory washing section-   14 power feeder-   141 feeding electrode-   142 receiving-side rotating member-   143 pressure applying device-   144 feeding terminal-   145 elastic member-   146 electrically conductive layer having a thin and cylindrical    shape-   147 electrode-   1401 bearing case-   1402 bracket-   1403 slide guide-   1404 bearing-   15 plating tub-   151 anode-   152 seal unit-   16 plating section-   17 post-processor-   18 reel-off section-   31 direct-current power supply-   32 voltmeter

DETAILED DESCRIPTION

Hereinafter, an exemplary embodiment of the present invention isdescribed referring to an example where the present invention is appliedto the manufacturing of a plastic film provided with a copper platedfilm on one surface thereof which is used for a flexible circuitsubstrate.

FIG. 1A is a schematic plan view of an example of a continuouselectrolytic plating apparatus for web according to an exemplaryembodiment. The apparatus is a multi-stage continuous electrolyticplating apparatus wherein a long film is wound off, plated, and reeledas a product roll. Main steps are handled by a wind-off section 12 whichwinds off a film 11 provided with a conductive film on one surfacethereof, in which a conductive film 112 made of very thin copper alloyis formed by means of the sputtering process or the like on one surfaceof a plastic film 111, from a roller-shape member on which the film 11is wound around, a preparatory washing section 13 which degreases andwashes the conductive film 112 of the film 11 which was wound off, aplating section 16 comprising a feeder 14 which supplies power by makingcontact with the conductive film 112 and a plating tub 15, apost-processor 17 which performs processes such as rust prevention,washing and drying in order to prevent the oxidation of a plated coatingfilm, and a reel-off section 18 which reels off the processed film. Thepreparatory washing section 13 may be omitted in the case where theconductive film 112 before the plating is clean, and the post-processor17 may also be omitted if it is necessary to do so.

In the plating processor 16, the film 11 with the conductive film isnipped with a feeding electrode 141 in contact with the conductive film112 and a receiving-side rotating member 142 in contact with the plasticfilm 111 in the feeder 14. The conductive film 112 is power-supplied bythe feeding electrode 141, and the conductive film 112 dipped in aplating bath in the plating tub 15 thereby becomes a cathode, and then,an electric plating circuit is formed between the cathode and an anode151. Then, the plating is performed. A slit as a passage for the film isprovided in a gateway of the plating tub 15, and a seal unit 152 whichcontrols the leak of the plating liquid from the slit by retaining theplating liquid in the plating tub 15 is provided. Suitable examples ofthe seal unit 152 are a seal unit which nips the film with two elasticrollers such as rubber rollers and a unit which controls an amount ofthe leaking liquid by controlling a gap between two plates.

A thickness of the plastic film 111 of the film 11 with the conductivefilm is preferably 5 μm-80 μm. Suitable materials thereof are polyesterresin and polyimide resin. In the case of a product for applications ofa semiconductor package or the like, for which heat resistance isdemanded, in particular, a polyimide film is more suitably used. Variousprocesses can be adopted when the conductive film 112 is formed. Forexample, the conductive film may be bonded to the film with an adhesive,or the conductive film may be directly formed on the film by means ofthe sputtering process, deposition process or the like. The bondingprocess in which the adhesive is used may be disadvantageous in that aheat resistant temperature of the adhesive is often lower than that ofthe film. Therefore, the conductive film is preferably directly formedon the film in view of heat resistance, and the sputtering process ispreferably adopted in view of manufacturing costs. A film thickness ofthe conductive film 112 is preferably 0.02 μm-0.5 μm, and morepreferably at least 0.08 μm in order to control any loss generated dueto a large electric resistance of the film, and at most 0.25 μM in viewof productivity.

FIG. 1B is a schematic view in which vicinity of the electrode isenlarged in an example of the feeder 14. The feeding electrode 141 andthe receiving-side rotating member 142, which are rotatably supported,are placed so that they face each other with the film 11 with theconductive film therebetween. A pressure is applied by a pressureapplying device 143, and the feeding electrode 141 is power-supplied bya feeding terminal 144. A spring or an air cylinder, for example, can beused as the pressure applying device 143. The electrode may be set onboth ends of the film, or may be set on one end only. FIG. 2 illustratesan example of a relationship between the pressure and electricresistance generated by the contact. When the contact resistance islarge, the Joule heat is unfavorably generated where the electrode andthe conductive surface contact with each other, and the conductive filmis thereby color-changed or altered. Therefore, the pressure to beapplied is suitably at least 2N per 1 mm of a contact width t betweenthe electrode and the conductive surface. The pressure to be applied ismore suitably at least 5N per 1 mm of the contact width, and even moresuitably at least 8N per 1 mm of the contact width in order to make thecontact more stable. When such a large pressure that exceeds 100N per 1mm of the contact width is applied, the contact resistance value isunlikely to largely reduce, while such a disadvantage that the structureis complicated or increased in size in order to withstand such a largepressure is generated. Therefore, the pressure to be applied isdesirably at most 100N. The pressure is obtained from the product of aspring constant and an amount of displacement in the case where thespring is used to apply the pressure, and obtained from a pressurereceiving area of an air cylinder and an air pressure in the case wherethe air cylinder is used to apply the pressure. A distance H from theend of the film to an inner-side edge of the feeding electrode ispreferably at most 20 mm in order to secure as a large region where thescratches or the like are not generated as possible. The distance H ismore preferably 5 mm-12 mm in order to secure the contact area betweenthe feeding electrode and the film conductive surface and also to obtainas a large region where they do not contact each other as possible.

The feeding electrode 141 and the receiving-side rotating member 142 arerotatably supported, and may be driven to be rotated as the film istransported. A torque may be aggressively supplied to one or both of therotating members so that they are driven. In the case where theelectrode is provided on the both ends of the film, the respectiveelectrodes are preferably rotated independently. In the case where theelectrodes are mechanically coupled with each other at the both endsthereof and then rotated as in the dumbbell-shape electrode recited inthe Patent Document 4, a slight velocity difference is likely to begenerated.

A material of the feeding electrode 141 is preferably a metallicmaterial having good conductivity such as copper or titanium, andfurther, a material having good conductivity and good corrosionresistance is more preferably used since the film may bring the platingliquid from the plating tub. FIGS. 1C and 1D illustrate a schematicsectional view of an exemplified structure of the feeding electrode 141.As shown in FIG. 1C, the electrode may be single-layered by means of amaterial, and a surface processing such as platinum plating may beapplied to the electrode surface. The dimension of the electrode isdesirably smaller so that the apparatus can be downsized. As apreferable constitution, as shown in FIG. 1D, an electrically conductivelayer 146 having a thin and cylindrical shape in which metal such asnickel or titanium is formed into a cylindrical shape having a thicknessat least 0.02 mm and at most 1 mm is embedded into a surface layer of anelastic member 145 such as rubber, and an electrode 147 is made tocontact the electrically conductive layer 146 so as to feed power. Then,the elastic member 145 is deformed by the pressure, and the thin andcylindrical electrically conductive layer 146 is accordingly deformed.As a result, the area contacting the film conductive surface can befavorably increased.

In the case where an elastic member is provided on an outermost layer ofthe receiving-side rotating member, a similar effect can be favorablyobtained. When the pressure at least 0.5 N per 1 mm of the contact widthis applied in the case of the rotating member in which the elasticmember is used as the rotating member, the contact resistance obtainedwhen the metallic rotating members are nipped with the pressure of 2 Nper 1 mm of the contact width can be similarly obtained, because therotating member in which the elastic member is used can be largelydeformed with a small force, which increases the contact area. Thecontact area is not so increased when the metallic rotating members arenipped with a large force. The contact area in this case may be verysmall, however, all of the currents flow into the small contact area,which significantly increases the Joule heat per unit area of thecontact section. In the case where the contact resistance value is thesame when the same current value is supplied, the Joule heat per unitarea is reduced to a half when the contact area is doubled, whichcontributes to the control of the temperature increase. Therefore, theincrease of the contact area by utilizing the deflection of the elasticmember leads to the prevention of heat-related problems, which issuitable particularly when large currents are supplied. According to thefindings obtained by the inventors of the present invention from theirexperiments, when the nipping pressure is applied such that the contactarea stays within the range of the formula 3, the power feed can befavorably realized without such intensive heat generation that may burnthe substrate. When the nipping pressure is applied such that thecontact area stays within the range of the formula 4, the power feed canbe favorably realized without the generation of heat shrinkage, dryingspot and the like. Q: threshold heat quantity factor in the formulas 3and 4 was obtained by the inventors of the present invention from theirexperiments such that an electrode having a certain contact area isconnected to a substrate provided with a conductive film having acertain thickness, currents are supplied, a volume of heat generated bythe Joule heat per unit area of an electrode contact section when such aheat-related problem as the heat shrinkage or combustion loss isgenerated, and a numeral value obtained by dividing the obtained heatvolume is multiplied by a safety ratio

$\begin{matrix}{\frac{I^{2} \cdot R}{Q \cdot t} \leqq A \leqq 1000} & {{NUMERAL}\mspace{14mu}{FORMULA}\mspace{14mu} 3}\end{matrix}$A: contact area between the feeding electrode and the webconductivesurface [mm²]I: current value supplied to the feeding electrode [A]R: contact resistance value in the contact between the feeding electrodeand the web conductive surface [Ω]t: thickness of the conductive surface where the feeding electrode andthe web conductive surface contact each other [mm]Q₁: threshold heat quantity factor [W/mm³]=5.5×10³

$\begin{matrix}{\frac{I^{2} \cdot R}{Q \cdot t} \leqq A \leqq 1000} & {{NUMERAL}\mspace{14mu}{FORMULA}\mspace{14mu} 4}\end{matrix}$A: contact area between the feeding electrode and the webconductivesurface [mm²]I: current value supplied to the feeding electrode [A]R: contact resistance value in the contact between the feeding electrodeand the web conductive surface [Ω]t: thickness of the conductive surface where the feeding electrode andthe web conductive surface contact each other [mm]Q₂: threshold heat quantity factor [W/mm³]=0.7×10³

Suitable examples of a material used for the elastic member are rubbersuch as nitrile rubber or fluororubber and resin such as polyester, andfluororubber superior in its chemical resistance is particularlysuitably used. A degree of rubber hardness in the elastic member ispreferably at least 40° and at most 90° in the JIS-A hardness. Athickness of the elastic member is not particularly limited, however ispreferably smaller than the contact width in order to prevent it fromdeflecting in the case where the hardness is too low.

The feeding terminal 144 is necessarily adapted to be rotatable andelectrically connected. A structure where the metallic electrodecontacts the feeding terminal or a connecting terminal such as a slipring or a rotary connector is suitably used.

A material used for the receiving-side rotating member 142 is, forexample, stainless, however, is not particularly limited. However, amaterial having corrosion resistance is preferably used because it maycontact the plating liquid brought by the film. The receiving-siderotating member 142 may have a single-layered structure or amulti-layered structure. A multi-layered structure comprising an elasticmember such as rubber on a surface layer thereof is preferably adoptedbecause the contact area between the film conductive surface and thefeeding electrode can be increased.

A roughness of the surface of the feeding electrode contacting the filmconductive surface is preferably Ra=0.1 μm-50 μm in terms of thearithmetic mean roughness regulated in the JIS B0601-2001. A surfacehaving a large unevenness, in other words, a surface in which thearithmetic mean roughness is large contributes to the increase of thecontact area because a surface area thereof is increased. However, too alarge roughness does not allow the film conductive surface to closelycontact it, and the actual contact area is thereby reduced. In order tosecure the contact area with an appropriate pressure, Ra=0.8 μm-6.3 μmis more preferable.

Referring to FIG. 1A again, the feeder 14 is provided only in front ofthe plating tub 15, however, may be provided only behind the plating tub15, before and after the plating tub 15 or inside the plating tub 15. Inthe case where the feeder 14 is provided inside the plating tub 15, theplating metal is deposited on the feeding electrode 141 itself, whichrequires a device for removing the plating metal and thereby complicatesthe apparatus structure. Therefore, the feeder 14 is preferably providedoutside the plating tub.

In the case where the surface resistivity of the conductive film 112 ofthe film 11 with the conductive film is at least 0.1Ω/□, a voltagerequired for supplying predetermined currents is increased as a distanceX from the feeding electrode to the gateway of the plating tub islarger, which increases power loss. Therefore, the distance X from thefeeding electrode to the gateway of the plating tub is preferably set sothat the numeral formula 5 is satisfied.

$\begin{matrix}{\frac{B}{2} < X \leqq \frac{500 \cdot N \cdot W}{\left( {I \cdot W \cdot L} \right)^{2} \cdot p \cdot {\log\left( \frac{t + W}{t} \right)}}} & {{NUMERAL}\mspace{14mu}{FORMULA}\mspace{14mu} 5}\end{matrix}$X: distance between the feeding electrode and the gateway of the platingtub which is the closest to the center of rotation of the rotatingmember in contact with the web in the transportation direction of theweb [mm]B: length of the feeding electrode in the transportation direction [mm]I: current density [A/dm²]W: width of the web conductive surface [mm]L: length of the plating tub [mm]ρ: conductive film surface resistivity of the film with the conductivefilm [Ω/□]t: contact width between the feeding electrode and the conductivesurface of the web in the width direction [mm]N: feeding electrode factor (2 in the case where it is provided on theboth sides, 1 in the case where it is provided on one side)

The numeral formula 5 was derived based on the findings obtained by theinventors of the present invention. The left part shows a lower limit ofX, which is a distance necessary to avoid any physical contact betweenthe feeder 14 which is placed outside of the plating tub and the platingliquid. The right part shows an upper limit of X. When an object iselectrically conducted, the Joule heat is generated. Such a range ofheat volume that do not affect the conduction is experimentallyobtained, and the volume of generated heat is calculated from the filmresistance from the feeding electrode to the plating tub and thesupplied current, and such X that is at most the heat volume which doesnot affect the conduction experimentally obtained earlier is obtained.The X is inversely proportional to the current density I and theresistivity p of the conductive film surface. 500 is a factorexperimentally obtained, in which the safety ratio and the like isconsidered.

The continuous electrolytic plating device described thus far is capableof manufacturing a product having a good surface quality, and can besuitably applied to the manufacturing a plastic film provided with aplated film. The continuous electrolytic plating device can be suitablyused for the manufacturing of applications of an electronic wiring, inparticular, to the manufacturing of applications of a flexible circuitsubstrate. The continuous electrolytic plating device is particularlyuseful for the manufacturing of a plastic film provided with a platedfilm used in applications of a semiconductor package or the like, forwhich a high surface quality is demanded in response to the need for afine processing because of a fine wiring pitch.

EXAMPLES

Below is described the present invention in detail referring to specificexamples. The present invention, however, is not particularly limited tothese examples.

Example 1

The device structure of the feeder is as shown in FIG. 1B. A bearingcase 1401, a slide guide 1403, a bracket 1402 and a pressure-applyingspring 143 were formed from stainless steel. A spring constant of thepressure-applying spring 143 was 14.7 N/mm. The feeding electrodeconstituted as shown in FIG. 10 and formed from titanium was used. Adisc-shape member constituting the section contacting the film had theouter diameter of 60 mm, and the thickness of 10 mm. The both-shoulderC1 chamfer was applied thereto, and the width contacting the film was 8mm. The arithmetic mean roughness of the contact surface was pursuant tothe arithmetic mean roughness regulated in the JIS B0601-2001. Thesurface roughness measuring device, “Surtronic 25”, manufactured byTaylor Hobson K. K., UK, was used to measure the surface roughness, and4.7 μm was obtained. “Rotary Connector MODEL 1250-SC”, manufactured byMercotac Inc., US, was attached to a shaft-end portion to allow power tobe supplied during the rotation. The receiving-side rotating member wasformed from stainless steel, and had the outer diameter of 100 mm, andthe thickness of 12 mm. The both-shoulder C1 chamfer was appliedthereto, and the width contacting the film was 10 mm.

FIG. 3 is a conceptual view illustrating a method for measuring thecontact resistance between the feeding electrode and the film conductivesurface. A film obtained by plating copper by 8.5 μm on one surface of apolyimide film having the thickness of 38 μm was nippingly placed suchthat the centers of the feeding electrode and the receiving-siderotating member in the thickness direction were both at a positiondistant by 5 mm from an end of a film having the width of 15 mm in thewidth direction, and one side of a power supply was connected to thefeeding terminal, while the other side thereof was connected to vicinityof the electrode contact section at a position distant by 12 mm from theend of the film in the width direction so as to obtain the circuitconfiguration shown in FIG. 3. Then, the resistance value was measured.The constant current of 0.5 A was supplied from a direct-current powersupply 31, a voltage was measured by a voltmeter 32, and a resistancevalue was calculated according to the Ohm's law. FIG. 4 shows ameasurement result in which the fluctuation of the resistance value wasmeasured while the pressure was changed. The surface resistivity of thefilm used then was pursuant to the JIS K7194-1994, and the surfaceresistivity measuring device, “Loresta-GP” MCP-T600, manufactured byMitsubishi Chemical Corporation, was used for the measurement. As aresult, 1.92×10⁻³Ω/□ was obtained.

The same measurement was conducted by using a film obtained such thatcopper alloy by 0.1 μm was formed by means of the sputtering process onone surface of a polyimide film having the thickness of 38 μm. A resultthereby obtained is shown in FIG. 9. The surface resistivity of theconductive film formed by means of the sputtering process was3.5×10⁻¹Ω/□.

FIG. 5 is a conceptual view illustrating a method for measuring theresistance value when a conducting length was changed. A film obtainedby plating copper by 8.5 μm on one surface of a polyimide film havingthe thickness of 38 μm was nippingly placed such that the centers of thefeeding electrode and the receiving-side rotating member in thethickness direction were both at a position distant by 5 mm from an endof a film having the width of 520 mm, and one side of a power supply wasconnected to the feeding terminal, while the other side thereof wasconnected to a position distant from the electrode contact position by500 mm in the transportation direction so as to obtain the circuitconfiguration shown in FIG. 5. Then, the resistance value was measured.The constant current of 0.5 A was supplied from the direct-current powersupply 31, a voltage was measured by the voltmeter 32, and theresistance value was calculated according to the Ohm' s law. A distancefrom the section where the feeding electrode and the film contact eachother to the measuring position in the film transportation direction was500 mm. FIG. 6 shows a measurement result in which the resistance valuewas measured while the distance from the feeding electrode to themeasuring position in the film width direction was changed.

A long polyimide film having the thickness of 38 μm and the width of 520mm was used, and the feeder was placed at one position such that thecenters of the feeding electrode and the receiving-side rotating memberin the thickness direction were both at a position distant by 5 mm froman end of the film. Then, the contact pressures of 10 N/mm and 20 N/mmper 1 mm of the contact width were applied, and the film was transportedat the velocity of 2 m/min. As a result, the rotation was obtained bythe film tension in either of the contact pressures, any deviation andcreases were not generated, and the generation of scratches was notdetected in other than the contact section.

It can be learnt from the foregoing results that, in the case where thepolyimide film provided with the copper plated film, which is used forapplications of the flexible circuit substrate, by the continuouselectrolytic plating apparatus in which the feeder is provided, thefeeding electrode and the like do not contact the center of the film inthe width direction, most of which will be included in a final product.As a result, a product in which surface flaws such as scratches arelessened can be obtained.

Example 2

A feeder structure similar to that of the Example 1 was used, thereceiving-side rotating member had the diameter of 90 mm and the widthof 6.5 mm in the contact width direction, and rubber having thethickness of 5 mm was wound around the surface layer. As the rubber,nitrile rubber at 80° in the JIS-A hardness (measured with a sampleplate having the thickness of 5 mm) was used.

Various tests similar to those of the Example 1 were performed, in whichthe feeder was used, and results shown in FIGS. 4, 6 and 9 wereobtained.

A long polyimide film having the thickness of 38 μm and the width of 520mm was used, and the feeder was placed at one position such that thecenters of the feeding electrode and the receiving-side rotating memberin the thickness direction were both at a position distant by 5 mm froman end of the film. Then, the contact pressures of 10 N/mm and 20 N/mmper 1 mm of the contact width were applied, and the film was transportedat the velocity of 2 m/min. As a result, any deviation and creases werenot generated, and the generation of scratches was not detected in otherthan the contact section in either of the contact pressures. Therotating member was driven to be rotated with the contact pressure of 20N/mm, however, the transportation could be more stable when the feedingelectrode was secondarily rotated because a large torque was necessaryfor the rotation.

It can be learnt from the foregoing results that, in the case where thepolyimide film provided with the copper plated film, which is used forapplications of the flexible circuit substrate, by the continuouselectrolytic plating apparatus in which the feeder is provided, thefeeding electrode and the like do not contact the center of the film inthe width direction, most of which will be included in a final product.As a result, a product in which surface flaws such as scratches arelessened can be obtained.

Example 3

A feeder structure similar to that of the Example 1 was used, thereceiving-side rotating member had the diameter of 90 mm and the widthof 12 mm in the contact width direction, and rubber having the thicknessof 5 mm was wound around the surface layer. As the rubber, nitrilerubber at 80° in the JIS-A hardness measured with a sample plate havingthe thickness of 5 mm was used.

Various tests similar to those of the Example 1 were performed, in whichthe feeder was used, and results shown in FIGS. 4 and 6 were obtained.

A long polyimide film having the thickness of 38 μm and the width of 520mm was used, and the feeder was placed at one position such that thecenters of the feeding electrode and the receiving-side rotating memberin the thickness direction were both at a position distant by 5 mm froman end of the film. Then, the contact pressures of 10 N/mm and 20 N/mmper 1 mm of the contact width were applied, and the film was transportedat the velocity of 2 m/min. As a result, it was confirmed that creaseswere generated in the film at the edge of the feeding electrode ineither of the contact pressures, however, the generation of scratcheswas not detected in other than the contact section which will be includein a final product. The rotating member was driven to be rotated withthe contact pressure of 20 N/mm, however, the transportation could bemore stable when the feeding electrode was secondarily rotated because alarge torque was necessary for the rotation.

It can be learnt from the foregoing results that, in the case where thepolyimide film provided with the copper plated film, which is used forapplications of the flexible circuit substrate, by the continuouselectrolytic plating apparatus in which the feeder is provided, thefeeding electrode and the like do not contact the center of the film inthe width direction, which will be included in a final product. As aresult, a product in which surface flaws such as scratches are lessenedcan be obtained.

Example 4

A feeder structure similar to that of the Example 1 was used, thereceiving-side rotating member had the diameter of 90 mm and the widthof 7 mm in the contact width direction, and rubber having the thicknessof 5 mm was wound around the surface layer. As the rubber,ethylenepropylene rubber at 40° in the JIS-A hardness measured with asample plate having the thickness of 5 mm was used. This feeder was usedas the feeder 14 in the plating apparatus shown in FIG. 1A, and thecurrent value was set to 170 A. Then, a continuous plating experimentwas conducted. A medium in which copper was formed by 7 μm as aconductive film on one surface of the 38 μm polyimide film, “Kapton EN”(manufactured by DU PONT-TORAY CO., LTD.) was used, and the nippingpressure was set to 5 N/mm. The contact area at the time was 200 mm².The contact resistance value was 30 mΩ, and the contact area rangecalculated when it is assigned to the formula 3 was 22 mm²≦A≦1,000 mm².The contact area was, therefore, within the calculated range.

As a result, the plating process was favorably performed withoutgenerating heat-related problems, for example, the medium may be burnt.

Comparative Example 1

A measurement similar to that of the Example 1 was conducted to aconventional roller-shape electrode. The roller-shape electrode had astructure in which a copper roller was attached to a brass shaft, anouter diameter of the roller was 80 mm and a surface length of theroller was 580 mm, and the center of the surface length of the rollerand the center of the film in the width direction were aligned with eachother.

FIG. 7 illustrates a method for measuring the contact resistance betweenthe feeding electrode and the film conductive surface. A film having thewidth of 520 mm was wrapped around so that the conductive surfacethereof contacted the roller surface. One side of a power supply wasconnected to the feeding terminal, while the other side thereof wasconnected to a position distant by 2 mm from and end of the film in thewidth direction on the feeding-terminal side and a position distant by 3mm from a position where the roller and the film started to separatefrom each other in the transportation direction. A weight M was attachedto near the center of the pendant film so that the film tension was setto 40 N-400 N, and the measurement was performed. In any of the settensions, the stability was obtained in 120 mΩ in the case of the copperplated film of 8.5 μm, and in 200 mΩ in the case of the copper alloysputtered film of 0.1 μm. It was confirmed that the Examples 1-3 showedthe resistance which was lower than that of the comparative example.

A circuit configuration shown in FIG. 8 was obtained, and therelationship between the conducting length and the resistance value wasmeasured with the film tension of 50 N. A result thereby obtained isshown in FIG. 6. The “position in the width direction” in the horizontalaxis shown in FIG. 6 corresponds to the “position in the widthdirection” shown in FIG. 8.

When the polyimide film having the copper plated film used forapplications of the flexible circuit substrate was manufactured by thecontinuous electrolytic plating apparatus in which the roller-shapeelectrode is adopted, scratches were generated 100%, and approximately10% of the generated scratches were such that could make a product to bejudged as an inferior product.

Summary of FIGS. 4, 6 and 9

1) FIGS. 4 and 9: Relationship between the pressure and resistance value

a) In the power feeding method according to the comparative example 1,the resistance value was 120 mΩ for the 8.5 μm plated film. In contrast,the Examples 1-3 showed the result in FIG. 4. Accordingly, it is knownthat the pressure at least 2 N/mm is preferably applied in any of theExamples 1-3 in order to obtain at most the resistance value accordingto the comparative example 1 (120 mΩ) so that the feeding capacity equalto that of the comparative example 1 (conventional technology) can beobtained.b) In the power feeding method according to the comparative example 1,the resistance value was 200 mΩ for the 0.1 μm sputtered film. Incontrast, the Examples 1-3 showed the result in FIG. 9. Accordingly, itis known that the pressure at least 2 N/mm is preferably applied in anyof the Examples 1-3 in order to obtain at most the resistance valueaccording to the comparative example 1 (200 mΩ) so that the feedingcapacity equal to that of the comparative example 1 (conventionaltechnology) can be obtained.c) The reduction of the resistance value in response to the increase ofthe pressure is more remarkable in the Examples 2 and 3 than in theExample 1. The reduction is thus more remarkable probably because thearea of the feeding electrode contacting the film conductive surface issignificantly increased by the deformation induced by the rubber used inthe receiving-side rotating member when the pressure is applied.d) The difference between the Examples 2 and 3 was generated probablybecause the resistance value was reduced because the contact width ofthe receiving-side rotating member was larger in the Example 3 than inthe Example 2, and the contact area was larger in the Example 3. Thefilm may undergo creases at the edge of the feeding electrode, however,this is not a problem in most cases because the relevant part will becut off and will not be included in a final product. However, thegenerated creases may cause troubles during the transportation, and theproduct width will be reduced because a removal margin is large when therelevant part is finally cut off and discarded. In order to avoid suchdisadvantages, therefore, the Example 2 is preferably adopted unless itcauses any problem in the resistance value. The Example 3 is preferablein the case where creases are hardly generated, or the creases, ifgenerated, will not cause any trouble during the transportation.2) FIG. 6: Relationship between the position of the film in the widthdirection and the resistance valuea) The power is supplied such that the electrode contacts the entirearea in the width direction in the comparative example, while the poweris supplied such that the electrode contacts only the end portion in theExamples 1-3, which possibly generates the irregularity in the powersupply in the width direction. Therefore, this issue was examined.b) As shown in FIG. 6, the resistance values ranging from 60 mΩ to 120mΩ were obtained in the comparative example 1, wherein such a largedifference as nearly twice was seen when the largest value and smallestvalue were compared to each other. It is assumed that such a largevariability is generated under the influence of the in-plane resistancevariability in the film conductive surface. The resistance values in theExamples 1-3 are as shown as below. The resistance value in the Example1 is in the range of 60-90 mΩ, the resistance value in the Example 2 isin the range of 25-40 mΩ, and the resistance value in the Example 3 isin the range of 10-20 mΩ, wherein the variation of the resistance valueis not in such a broad range as in the comparative example. Thus, it canbe said that the feeding irregularity in the width direction, which iscomparable to that of the conventional technology, could be surelyobtained.

The present invention is not limited to the manufacturing of a filmhaving a copper plated coating film, and can be applied to anelectrolytic plating apparatus in which metal is used, and anelectrolytic plating apparatus in which a medium other than a resin filmis used. However, the application of the present invention is notlimited to any of them.

1. A power feeding method for an electrolytic plating method forelectrolytically plating a web comprising a conductive surface as atleast one of the surfaces thereof in a plating tub, the methodcomprising: continuously transporting the web, nipping the web with atleast two rotating members so that the web faces one end thereof or bothends thereof in a width direction, at least one of the rotating membersis used as a feeding electrode and comprises an electrically conductivelayer on a surface layer thereof so that the web in the plating tub ispower-supplied, and the feeding electrode further comprises an elasticlayer inside the electrically conducive layer, or a rotating member on areceiving side which nips the web together with the feeding electrodecomprises an elastic member on a surface layer thereof, or the feedingelectrode comprises the elastic layer inside the electrically conductivelayer and the rotating member on the receiving side which nips the webtogether with the feeding electrode comprises the elastic member on thesurface layer thereof, pressing the electrode onto the web only in aregion distant by at least 0.5 mm and at most 20 mm from the end of theweb in the width direction with a contacting pressure of at least 0.5 Nand at most 100 N per 1 mm of a contact width in the width direction,and rotating the rotating members about the same velocity to a velocityof the transportation of the web.
 2. The power feeding method as claimedin claim 1, wherein the electrode is placed outside of the plating tub,and power is supplied in a section of the web targeted for the platingonly in an upstream side and/or a downstream side of the plating tub ina transportation direction.
 3. The power feeding method as claimed inclaim 1, wherein the web is transported in a longitudinal direction sothat the width direction thereof is along a vertical direction.
 4. Thepower feeding method as claimed in claim 1, wherein the contact widthbetween the receiving-side rotating member and the web in the widthdirection is larger by at least 1 mm and at most 15 mm than a contactwidth between the feeding electrode and the web in the width direction.5. The power feeding method as claimed in claim 1, wherein the contactwidth between the receiving-side rotating member and the web in thewidth direction is smaller than the contact width between the feedingelectrode and the web in the width direction.
 6. The power feedingmethod as claimed in claim 1, wherein the contact pressure is applied sothat a contact area where the feeding electrode contacts the conductivesurface satisfies the following numeral formula: $\begin{matrix}{\frac{I^{2} \cdot R}{Q \cdot t} \leqq A \leqq 1000} & {{NUMERAL}\mspace{14mu}{FORMULA}\mspace{14mu} 1}\end{matrix}$ A: contact area between the feeding electrode and theconductive surface [mm²] I: current value supplied to the feedingelectrode [A] R: contact resistance value in the contact between thefeeding electrode and the conductive surface [Ω] t: thickness of theelectrically conductive layer on the conductive surface where thefeeding electrode contacts the conductive surface [mm] Q: threshold heatquantity factor [W/mm³]=5.5×10³.
 7. A power feeding method for anelectrolytic plating method for electrolytically plating a web havingconductivity on surfaces thereof in a plating tub, the methodcomprising: continuously transporting the web in the plating tub,nipping the web with at least two rotating members so that the web facesone end thereof or both ends thereof in a width direction, at least oneof the rotating members is used as a feeding electrode and comprises anelectrically conductive layer on a surface layer thereof so that the webin the plating tub is power-supplied, and the feeding electrode furthercomprises an elastic layer inside the electrically conducive layer, or arotating member on a receiving side which nips the web together with thefeeding electrode comprises an elastic member on a surface layerthereof, or the feeding electrode comprises the elastic layer inside theelectrically conductive layer and the rotating member on the receivingside which nips the web together with the feeding electrode comprisesthe elastic member on the surface layer thereof, pressing the electrodeonto the web only in a region distant by at least 0.5 mm and at most 20mm from the end of the web in the width direction with a contactingpressure of at least 2 N and at most 100 N per 1 mm of a contact widthin the width direction, and rotating the rotating members about the samevelocity to a velocity of the transportation of the web.
 8. A powerfeeding method for use in a process for electrolytically plating a webhaving a conductive surface, the method comprising: nipping the web withat least two rotating members; using at least one of the rotatingmembers as a feeding electrode to supply power to the web in a platingtub, the feeding electrode comprising an elastic layer inside theelectrically conducive layer, or a rotating member on a receiving sidewhich nips the web together with the feeding electrode comprises theelastic member on a surface layer thereof, or the feeding electrodecomprises the elastic layer inside the electrically conductive layer andthe rotating member on a receiving side which nips the web together withthe feeding electrode comprises the elastic member on the surface layerthereof; pressing the feeding electrode onto the web only in a regionspaced by at least 0.5 mm and at most 20 mm from the end of the web inthe width direction with a contacting pressure of at least 0.5 N and atmost 100 N per 1 mm of a contact width in the width direction; androtating the rotating members at about the same velocity as a velocityof the web.